Astra by Cesbo - Talk to Alexa anywhere, from your iPhone
Voice Principles - Guiding principles for voice design, all in one place
Reverb - Use Alexa on your Mac, iPhone and Android
Alexa Skill Kit - Effortless Alexa Skill development with AWS Lambda
Amazon Blueprints - Create your own Alexa Skill in minutes
Voiceflow - Build voice apps in your browser without coding